RE: Fuel? Glow plugs?
I don't know about the pin being a real problem with the 4995's tranny, but you should loosen up the slipper just a bit, or don't land jumps under full acceleration.. thats usually the cause... You will also trash the diffs that way.. (experience here)...
for the spur and bell combo... smaller bell and larger spur is more off the line power, but less top end.. larger bell and smaller spur is slower off the line with more top end... a word of advice here... its much easier and cheaper to replace the spur gear than the clutch bell.. Go up 2 teeth and see what you get.. you can get a couple of spur gears for the price of one clutch bell... and you should have spares anyway...
Enjoy the truck... try not to run it too cold, under 200 is too cold... just lean it a tiny bit to bring the temps up a bit... It wil be even stronger... As for the traxxas plugs.. I have a bunch as spares.. they work ok, but don't last nearly as long as OS and Mccoy...